The present invention relates generally to digital imagesetting systems and the application of specific design information to the process of document layout and publication. In particular, the present invention relates to a method of defining a document design model and an automatic process utilizing the design model to produce user documents with a user selected typeface in a user selected format in conformance with the design model.
In recent years word processing programs, computers, laser printers and other peripherals have become so powerful that it is now possible for users in small companies and large corporations alike to produce the majority of their business documents in-house. These documents include, for example, company newsletters, quarterly reports, new product announcements and customer proposals. Prior to the advent of desktop publishing technology, the majority of this work was sent out to professional graphic designers and typesetters for production.
While the page layout and style sheet programs provided by the current generation of desktop publishing technology are designed to allow a user to quickly produce well-designed documents, these projects typically become the task of the secretarial staff, who have neither the training in graphic design, nor the time to master the archaic, slow and complex user interfaces of current page layout programs. To take advantage of the graphic possibilities of laser printers for even simple projects requires command of complex professional coding in a word processor program. While carrying a normal work load, it may take a skilled person as long as six to nine months to become fully proficient with current desktop publishing programs. At best, these programs are slow to sue, invite errors and the user still doesn't understand how to design a good looking document. For each new project a user must program into the desired document the typeface from a large selection of available typefaces, the type size, or font, and the document format, i.e., the number of columns, the size of columns, section and column headings, headings and footers. Further, the appropriate typeface, style and size relative to the text typeface must be selected for the heading typeface to provide the proper emphasis. Each of these decisions is complicated by its own set of rules. The major reason for this complexity is that the current desktop publishing programs have evolved from the process wherein each of a series of design decisions is made, after consideration, by a professional graphics designer while creating and producing a document.
Current desktop publishing programs provide little or no guidance on choices, selection or placement of design elements, such as column layout, placement of page numbers, body text style, style and placement of titles and heads, and so on. Where choices are offered, they are often arbitrary and bear little relation to other design elements or decisions. In most cases, the user is free to override or modify the choices, eliminating what little value there might be in the predefined styles. Ultimately, there is no assurance that design decisions can be transmitted, applied correctly, or enforced.
Likewise, current desktop publishing systems do not address either problems of changing fonts or the use of a second (or third) accent typeface for headlines and titles. For example, if the typeface used in a 30 page report is changed from Helvetica to Times Roman, the body of the text shrinks from 30 to 22 pages. All the careful work and time expended ensuring that the last paragraph on page three did not spill over to page four and that each headline is properly placed must be done over again. At the same time, the overall look or style of the document changes, due to the change in character proportions and the ratio between filled areas (occupied by the actual text) and open areas (blank space between lines of text). Further, selection of accent typefaces for titles and headlines must be done empirically. There are no rules or processes provided to select an accent typeface (either manually or automatically) while guaranteeing that such a choice will provide sufficient contrast and emphasis between the typeface used for the text and the typeface used for the title or headline.
A typical document can be thought of as comprising a set of design elements--column layout, bodytext formatting, the bodytext itself, titles, graphic elements, and so on--placed on one or more pages. Each design element may appear in several different styles within the document, or a single style may be used throughout. The art of graphic design consists of defining styles of design elements, then combining those elements on a page to achieve a certain effect. As with any art, this skill takes both training and talent, and the knowledge and techniques are not easily transmitted nor learned.
The size of type appropriate for the document format varies between typefaces and depends on the design of the typeface. Typically, type size refers to the height of the type and is measured in units of picas and points (6 picas to the inch, 12 points to the pica). However, a reader reacts to type based on what it looks like, rather than its size, i.e., the interaction between the sizes of several elements and not on the height alone. Types of the same size may well have different widths and proportions. Conventional use of point size to specify the size of typefaces leads to irregular readability and copyfit, i.e., the amount of text in a given area of the document, between identical documents using different typefaces of the same point size.
Point size is the measurement from the highest point of the ascender to the lowest point of the descender of the lowercase characters in the typeface, along with a small increment for clearance (as shown in FIG. 1). The spaces above and below the characters are normally just sufficient to visually separate subsequent lines of type. Interline spacing, the distance in point size units from one baseline to the next, typically will be the same or somewhat greater than the type size being used.
The proportion of the height, and width, of the lowercase letters to the overall height of the letters determines the apparent size of the type. Thus, the 10-point type of one typeface will not necessarily appear to be the same size as the 10-point type of another typeface. Similarly, the number of characters in a line of one typeface will typically be different from that in a line of another typeface of the same point size. Since the size of uppercase (capital) letters varies, their height is not often used as a standard of measure. Further, point size does not relate directly to the factors that control copyfit, readability of the text and other design considerations. Those factors are principally the width of the lowercase characters, including the space to either side of them, the height of the lowercase characters (referred to as x-height), and the open or blank space from the top of one lowercase letter to the bottom of the same character on the next line up (referred to in the following description as x-space).
When the point size is used in specifying text, all other measurements, such as interline spacing and line length, must be evaluated and the point size, line length and interline spacing adjusted by an expert typographer to accommodate one of the available point sizes if rough equivalence of design effect (such as readability) and copyfit are to be achieved. Traditionally, use of this measurement was essential when it defined the key dimension of the metal blocks on which each character was cast, or when it identified key steps in available mold liners, lens stops and other key mechanical and optical stops and controls in the mechanisms of typesetting machines that controlled the size of the type, the length and assembly of the line and the places in which the lines were to be located, one below another.
Traditionally, when one changed from one typeface to another, the whole point size that would yield a result closest to that desired is chosen, and a skillful typographer, working with allowable spacing increments, must then adjust line length, space between lines, interword spacing and sometimes intercharacter spacing until a reasonable rendition of the text was obtained in the typeface. When measured against a standard, or against renditions in other typefaces, copyfit, design effect and readability of the same text vary.
Typically, emphasis is achieved in a section heading or headline by increasing the size of the textface used for the heading, and by including additional spacing between the characters. Frequently the emphasis is increased by using another member of the same typeface family, for example, boldface, italic or bold italic. A further degree of emphasis can be obtained by changing to another typeface family suitable for the heading. However, while some pairs of typefaces work well together, others do not. Most poor combinations lack sufficient difference between the pairs of typefaces. In combinations lacking sufficient contrast, the heading or display typeface appears as a mismatch to the text typeface (referred to a "textface") rather than an emphasis. By measuring the factors that effect the difference between the textface and the proposed heading typeface, an adequate degree of contrast can be assured. Typically, a trained professional typographer is required to choose a good combination.